Our limited knowledge on this subject suggests that bison may be infected for extended periods, in some instances years, before developing MCF. More work is needed on this aspect of the disease.

The best one to use for diagnosing active disease is the PCR test. Blood collected into an EDTA-anticoagulant tube (purple-top tube) is the best sample to obtain from live animals. Both the PCR test and a newly developed serological test can be run on one purple-top blood sample. The carcass of an animal that dies of MCF-like signs should be examined post-mortem by your veterinarian or better still a pathologist at a veterinary diagnostic laboratory.

Our limited knowledge on this subject suggests that bison may be infected for extended periods, in some instances years, before developing MCF. More work is needed on this aspect of the disease. A recent study performed by a veterinary epidemiologist in Canada, Dr. John Berezowski at WCVM in Saskatoon, demonstrated that bison develop clinical signs as soon as 52 days and as late as 8 months after exposure to infected sheep.

We are doing a study to establish this. It clearly happens, but the percentage is low. No precise figures are available yet. Many factors are likely to affect the probability that a subclinically affected bison will develop clinical disease. One of the most important of these is stress.

With currently available test methods, between 15 and 23%. This is a minimal figure. No test is perfect. It is entirely possible that the tests currently being used for identifying infected normal bison miss a significant percentage of animals. The true rate of subclinical infection could be significantly higher than this.

There is no reason at this time why such animals should be culled. An important question we are trying to answer is whether healthy test-positive bison are at a significantly higher risk of developing MCF compared to healthy test-negative bison.

Yes. Bovine viral diarrhea, salmonellosis and pneumonia complex, among others, can be confused with MCF: Testing sick animals is the key to establishing an accurate diagnosis.

Epidemiological studies of field outbreaks strongly suggest that sheep infected with OvHV-2 are the principal source of MCF outbreaks in bison and cattle. A strong association between outbreaks in cattle and recent exposure to sheep has been documented repeatedly since 1929. Recent data indicate that a similar pattern occurs in bison. In some outbreaks, however, no sheep were in the vicinity immediately prior to the first case being identified.

Most infections are characterized by depression, separation from the rest of the herd, loss of appetite, and in many bloody diarrhea. Unlike MCF in cattle, discharge from the eyes and nasal passages of affected bison is minimal. Animals develop a fever and may pass bloody urine. The clinical course is generally 1 -7 days. Most animals die within 3 days of developing clinical signs.

Animals older than 6 months, particularly if stressed by bad weather, transportation and handling. Large outbreaks occur in feedlots, where stress due to crowding is likely.

Following transmission, the MCF virus is presumed to infect lymphoid tissues (spleen and lymph nodes) and cells lining the gut, urogenital tract and nasal passages. The severe inflammation generally causes gastroenteritis, with widespread formation of ulcers particularly in the large bowel. This is the basis for bloody diarrhea, a common and useful diagnostic sign of MCF in bison.

MCF virus is transmitted by sheep in most instances. There is no documented evidence of person-to-bison transmission. Normal veterinary infection control precautions should be followed when caring for a bison suspected to have this viral infection.

Natural infections occur in many species of deer such as elk, reindeer and moose, as well as a variety of exotic ruminants. The disease can be transmitted experimentally to laboratory species, but there is nothing to indicate these species are involved in natural transmission. MCF was recently reported in pigs for the first time.

Three tests are available: histopathology, serological testing for MCF and an OvHV-2 specific test using the polymerase chain reaction (PCR).

We are aware of cases in 11 states (Utah, Wyoming, Colorado, Montana, California, Oregon, Ohio, Kansas, Nebraska, North and South Dakota) and three Canadian provinces (Saskatchewan, Ontario and Alberta). The disease is widespread in the bison industry and is commonly misdiagnosed due to lack of specific clinical signs.

In most instances by contact with sheep. The virus is shed from the nasal passages. It is not clear precisely how the virus is transmitted from sheep to bison, but it is probably via the nose and/or mouth. There may be other avenues of transmission that have not yet been recognized.

We think it is rare. There are inherent problems in tracking diseases like MCF in wild bison. The number of studies of MCF in public herds is small.

far as is known, the disease has been present for hundreds of years. However, it has been recognized as a defined disease only within the past 80 years or so in the U.S. Reports of an MCF-Iike disease in cattle in North America appeared as early as the 1920s. The first well-documented case of MCF in bison occurred in South Dakota in 1973 and was reported in the scientific literature in 1977.

There is no evidence that transmission occurs horizontally from one bison to another. Currently we are doing a study supported in part by the National Bison Association to establish whether bison-to-bison transmission is a factor in natural outbreaks.

Humans—Most humans infected with the virus are not aware that they have contracted it. If a person does become ill, clinical signs are usually mild and include fever, headache, body aches and, in some cases, skin rash and swollen lymph nodes. Signs of more severe infection include high fever, neck stiffness, muscle weakness, convulsions and paralysis. Death rates associated with severe infection range from 3% to 15% and are highest among the elderly.

All natural H5N1 highly pathogenic avian influenza (HPAI) infections in domestic cats reported to date appear to have been associated with outbreaks in domestic or wild birds and acquired through ingestion of raw meat likely infected with the H5N1 HPAI virus. Fortunately, there is no evidence to date that domestic cats play a role in the natural transmission cycle of H5N1 HPAI viruses.

There is not enough information available about H5N1 highly pathogenic avian influenza (HPAI) infection in dogs to know how infection would develop. Domestic cats in Europe appear to have become infected by eating infected poultry or wild birds. Details concerning a case of H5N1 infection in a dog in October 2004 were recently published; the dog was infected after it ate the carcass of an infected duck. View the report on the CDC Web site.

You will need to install a good antivirus package such as AVG or update the definitions of your existing software and run a full scan. Also, you might want to visit http://windowsupdate.microsoft.com/. just to make sure that your computer is fully updated with the latest security patches.

The exact time to develop a vaccine for the H5N1virus is unknown, but it estimated that it will take four to six months.

Yes. There are generally no lesions in the fetus or placenta. It is assumed that abortion is a result of illness in the dam, rather than infection of the fetus. Dams die shortly after they abort.